The only real way is to measure it yourself.

 

CAE-2006 measurements are truest, before them manufacturer could pull numbers out of thin air pretty much.

 

Truest in the sense that they garantee a minimum output. But the amp can still be severly underated. You can have a CEA rating of 50watts x 4 but the amp actually produces more. It's only good for minimum.

Here is a great example, the RF 25 to life. This is a birth certificate of the power 1000 CEA rated at 50 watts X 4 for the front channels as can be seen here on their web site:
http://www.rockfordfosgate.com/produ..._id=101755&loc

 

very interesting guys. thanks. I learned alot about CAE-2006. Rockford Fosgate rates their amps at "less than or equal" (<=) 1%. I noticed that Kicker rates their amps at 1%. I suppose CAE-2006 is to stop overating and not underating.

I was just trying to compare apples to apples. I didn't want precise numbers but a good guess. I sorta answered my question in my quote.

 

Actually, if I remember correctly, I read somewhere, that CEA-2006 is on the nose rating. Rating something conservatively, or underrating would be missing the whole point. Like I see your Fosgate sheet, and it says it is rated 150x4, but CEA rated it honestly at 106x4. My Steg is rated 245x2, and their CEA rating is 255x2. It seems, that according to CEA some amps are underrated, so are overrated, that's why CEA is there to clear up the manufacturer's BS. I also, found some anecdotal evidence of my Steg doing 267 watts a side in a test by a customer, but he also rated it at 69% efficiency, which is pretty hard to swallow, as it is an AB Class amp, so I figured something fishy was going on, maybe there was hidden agenda happening.

 

Actually the first amp should be exactly 60 watts with the CEa rating. The difference?
Voltage.

60W \ 14.4V = 4.166666A
So lets plug that into the old voltage and see what happenes
4.166666A x 13.8V = 57.5W

Bottome line those amps will make the exact same power at the same voltage. I am sure that random THD figure will also be very similar for both at the same output.

 

So your saying that two SAME amps will make the SAME power with the SAME THD figures! I agree!

I was trying to show the difference between the old way and the new way that Kicker rated the same amp with different THD figures!

 

why don't you just hook them both up and use the one that sounds best to you. Or you could just use the new one as it's probably been abused less. As for comparing by the numbers just because somthing is tested using CEA standards doesn't mean the numbers aren't skewed in some way. It just means that anything tested with those standards is tested the same way. There really isn't a way to compare the old testing standards to CEA. Use them both and keep the one you like best!

 

I will add that once you set the amp up, when you play em as loud as hey will go, you will see around 1% THD regarless of wich one you choose.